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.Dd May 31 2017
.Dt LIBBSD 7
.Os
.Sh NAME
.Nm libbsd
.Nd utility functions from BSD systems
.Sh DESCRIPTION
The
.Nm libbsd
library provides a set if compatibility macros and functions commonly found
on BSD-based systems.
Its purpose is to make those available on non-BSD based systems to ease
portability.
.Pp
The library can be used in an overlay mode, which is the preferred way, so
that the code is portable and requires no modification to the original BSD
code.
This can be done easily with the
.Xr pkg-config 3
library named
.Pa libbsd-overlay .
Or by adding the system-specific include directory with the
.Pa bsd/
suffix to the list of system include paths.
With
.Nm gcc
this could be
.Ar -isystem ${includedir}/bsd .
In addition the
.Dv LIBBSD_OVERLAY
pre-processor variable needs to be defined.
The includes in this case should be the usual system ones, such as
.In unistd.h .
.Pp
The other way to use the library is to use the namespaced headers,
this is less portable as it makes using
.Nm libbsd
mandatory and it will not work on BSD-based systems, and requires
modifying original BSD code.
This can be done with the
.Xr pkg-config 3
library named
.Pa libbsd .
The includes in this case should be namespaced with
.Pa bsd/ ,
such as
.In bsd/unistd.h .
.Pp
The package also provides a
.Pa bsd-ctor
static library that can be used to inject automatic constructors into a
program so that the
.Fn setproctitle
function gets invoked automatically at startup time.
This can be done with the
.Xr pkg-config 3
library named
.Pa libbsd-ctor .
.Sh HEADERS
The following are the headers provided by
.Nm libbsd ,
that extend the standard system headers.
They can work in normal or overlay modes, for the former they need to
be prefixed with
.Pa bsd/ .
.Pp
.Bl -tag -width 4m -compact
.It In bitstring.h
.It In err.h
.It In getopt.h
.It In libutil.h
.It In md5.h
.It In netinet/ip_icmp.h
.It In nlist.h
.It In readpassphrase.h
.It In stdio.h
.It In stdlib.h
.It In string.h
.It In stringlist.h
.It In sys/bitstring.h
.It In sys/cdefs.h
.It In sys/endian.h
.It In sys/poll.h
.It In sys/queue.h
.It In sys/time.h
.It In sys/tree.h
.It In timeconv.h
.It In unistd.h
.It In vis.h
.It In wchar.h
.El
.Pp
The following is a
.Pa libbsd
specific convenience header, that includes some of the extended headers.
It only works in non-overlay mode.
.Pp
.Bl -tag -width 4m -compact
.It In bsd/bsd.h
.El
.Sh DEPRECATED
Some functions have been deprecated, they will emit warnings at compile time
and possibly while being linked at run-time.
This might be due to the functions not being portable at all to other
systems, making the package not buildable there; not portable in a correct
or non-buggy way; or because there are better more portable replacements now.
.Pp
This is the list of currently deprecated macros and functions:
.Bl -tag -width 4m
.It Fn fgetln
Unportable, requires assistance from the stdio layer.
An implementation has to choose between leaking buffers or being reentrant
for a limited amount of streams (this implementation chose the latter with
a limit of 32).
Use
.Fn getline 3
instead, which is available in many systems and required by
.St -p1003.1-2008 .
.It Fn funopen
Unportable, requires assistance from the stdio layer or some hook framework.
On GNU systems the
.Fn fopencookie
function can be used.
Otherwise the code needs to be prepared for neither of these functions being
available.
.El
.Pp
In addition, the MD5 set of digest funtions are now provided by the
.Nm libmd
companion library, so it is advised to use that instead, as the ones
provided in
.Nm libbsd
might disappear on the next SONAME bump.
.Sh SEE ALSO
.Xr arc4random 3bsd ,
.Xr bitstring 3bsd ,
.Xr byteorder 3bsd ,
.Xr closefrom 3bsd ,
.Xr errc 3bsd ,
.Xr expand_number 3bsd ,
.Xr explicit_bzero 3bsd ,
.Xr fgetln 3bsd ,
.Xr fgetwln 3bsd ,
.Xr flopen 3bsd ,
.Xr fmtcheck 3bsd ,
.Xr fparseln 3bsd ,
.Xr fpurge 3bsd ,
.Xr funopen 3bsd ,
.Xr getbsize 3bsd ,
.Xr getpeereid 3bsd ,
.Xr getprogname 3bsd ,
.Xr heapsort 3bsd ,
.Xr humanize_number 3bsd ,
.Xr md5 3bsd ,
.Xr nlist 3bsd ,
.Xr pidfile 3bsd ,
.Xr queue 3bsd ,
.Xr radixsort 3bsd ,
.Xr readpassphrase 3bsd ,
.Xr reallocarray 3bsd ,
.Xr reallocf 3bsd ,
.Xr setmode 3bsd ,
.Xr setproctitle 3bsd ,
.Xr stringlist 3bsd ,
.Xr strlcpy 3bsd ,
.Xr strmode 3bsd ,
.Xr strnstr 3bsd ,
.Xr strtonum 3bsd ,
.Xr timeradd 3bsd ,
.Xr timeval 3bsd ,
.Xr tree 3bsd ,
.Xr unvis 3bsd ,
.Xr vis 3bsd ,
.Xr wcslcpy 3bsd .
.Sh HISTORY
The
.Nm libbsd
project started in the Debian GNU/kFreeBSD port as a way to ease porting
code from FreeBSD to the GNU-based system.
Pretty early on it was generalized and a project created on FreeDesktop.org
for other distributions and projects to use.
.Pp
It is now distributed as part of most non-BSD distributions.
